This invention relates to the art of surgical tools and has particular relationship to tools for use in the implanting of a heart pacer. A typical heart pacer is described in Purdy, et al, U.S. Pat. No. 3,866,616. Such a pacer is implanted in the body of the host, in the case of a human being, in the chest or abdomen. The heart pacer includes an electrical circuit for producing electrical pulses. This circuit is electrically connected to the heart through a catheter which has a terminal (or, in the case of a bi-polar circuit, a pair of terminals) that is inserted into a socket which is connected to the electrical circuit. The terminal is secured by a set screw screwed into the heart pacer laterally of the socket.
Surgeons who implant the pacers have in general followed the practice of screwing the set screw tightly into the pacer so that its tip engages, and becomes cold welded to, the terminal. This practice alone has not proven entirely satisfactory. It has been found that there is electrical leakage through body fluids which contact the terminal directly and also through the set screw. To suppress this electrical leakage some surgeons have adopted the practice of plugging the opening in which the set screw is inserted, and which provides access to the body fluids, with a silicone-rubber cement during the implantation. This has not proven satisfactory. A preferred practice is to plug the opening with a silicone-rubber plug from whose periphery O-rings extend. The set screw is screwed in and the plug is plugged in during the implantation and this invention concerns itself with a tool for carrying out this operation.
In accordance with prior art practice, the surgeon carried out this operation with the aid of a hemostat or like instrument or with his fingers. With this practice the plug was not properly seated to produce an effective seal in the opening. At times the plug, being very small, was lost in the operating room or could even be left in the patient.
It is an object of this invention to overcome the difficulties and disadvantages of the prior art and to provide a tool both for screwing in the set screw of a heart pacer and for effectively sealing the set screw and the terminal of the pacer against penetration of body fluids during implantation.